TAS‐115 inhibits PDGFRα/AXL/FLT‐3 signaling and suppresses lung metastasis of osteosarcoma

Osteosarcoma is the most common malignant bone tumor in adolescence and childhood. Metastatic osteosarcoma has a poor prognosis with an overall 5-year survival rate of approximately 20 %. TAS-115 is a novel multiple receptor tyrosine kinase inhibitor that is currently undergoing clinical trials. Using the mouse highly lung-metastatic osteosarcoma cell line, LM8, we showed that TAS-115 suppressed the growth of subcutaneous grafted tumor and lung metastasis of osteosarcoma at least partially through the inhibition of platelet-derived growth factor receptor alpha, AXL, and FMS-like tyrosine kinase 3 phosphorylation. We also show that these signaling pathways are activated in various human osteosarcoma cell lines and are involved in proliferation. Our results suggest that TAS-115 may have potential for development into a novel treatment for metastatic osteosarcoma.